config.ini cannot be loaded

Hi, I am new to phalcon.I am using the INVO example on windows.There is a line of code '$config = new ConfigIni(APP_PATH . 'app/config/config.ini');' in 'invo/public/index.php'. Since it is in windows, I changed the code to be '$config = new ConfigIni(APP_PATH . 'app\config\config.ini');'.

But it does not work. When I run this file ,it says 'beforeConfiguration file 'C:\Users\Rambo\Documents\My Web Sites\EmptySite1\app\config\config.ini' cannot be loaded'.